1. Field of the Invention
The present invention relates to planar light source device for generating planar light, for example, a planar light source device used in a liquid crystal display device.
2. Description of the Related Art
A prior art planar light source device is described here with reference to FIG. 9 and FIG. 10. FIG. 9 is a diagram showing the structure of a planar light source device used in a liquid crystal display device, for example. In this diagram, reference numeral 1 is a frame member, which restricts the position of a linear light source, light guide plate, lamp reflector, optical sheet, and the like. Reference numeral 3 is an optical sheet. The optical sheet 3 is mounted on the upper face of a light guide plate, or the like, whose position is restricted by the frame member 1. This optical sheet 3 does not have a fixed position on the edge, where the linear light source is installed, and generally, it is attached to the frame member 1 on the shorter edge thereof, where the linear light source is not installed.
FIG. 10 shows the installation configuration of the optical sheet 3 and the frame member 1. This configuration shows a section along Bxe2x80x94B in FIG. 9. In the diagrams, reference numeral 4 is a light guide plate, and 12 is an adhesive material, such as double-sided tape, or the like. The optical sheet 3 is fixed to the frame member 1 by the adhesive material 12.
In prior technology of this kind, since the optical sheet is attached to the frame member by means of an adhesive material, such as double-sided tape, or the like, the installation task is complicated, and furthermore, it is difficult to perform this installation task with good accuracy.
In view of the foregoing, it is an object of the present invention to provide a planar light source device in which a position of an optical sheet is regulated by means of a simple structure.
It is another object of the present invention to provide a planar light source device in which a position of a lump reflector is regulated by means of a simple structure.
It is further object of the present invention to provide a planar light source device which enables to expand the optical sheet further up to the upper face of the light guide plate, thereby enabling frame narrowing, whilst also makes it possible to suppress incidence of light from the upper face of the light guide plate.
According to one aspect of the present invention, for achieving the above-mentioned objects, there is provided a planar light source device comprising a linear light source, a light guide plate for guiding light from the linear light source through the whole plane thereof, a lamp reflector for reflecting light from the linear light source in the direction of the light guide plate, an optical sheet positioned on the light output face of the light guide plate, and a frame member for regulating the positions of the linear light source, the light guide plate, the lamp reflector and the optical sheet, wherein the position of the optical sheet in the planar direction thereof is regulated by the side face portion of a protruding section formed in a portion of the frame member.
Consequently, it is possible to regulate a position of an optical sheet by means of a simple structure.
According to other aspect of the present invention, for achieving the above-mentioned objects, there is provided a planar light source device wherein the apex portion of the protruding section contacts the lamp reflector and forces the lamp reflector against the light guide plate.
Consequently, it is possible to regulate a position of a lump reflector by means of a simple structure.
According to other aspect of the present invention, for achieving the above-mentioned objects, there is provided a planar light source device wherein the apex portion of the protruding section contacts the light guide plate, and the side face portion of the protruding section opposite to the side face portion regulating the position of the optical sheet is disposed in such a manner that it coincides approximately with the end face of the light guide plate.
Consequently, it is possible to expand the optical sheet further up to the upper face of the light guide plate, thereby enabling frame narrowing, whilst also makes it possible to suppress incidence of light from the upper face of the light guide plate.
The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for purpose of illustration only and are not intended as a definition of the limits of the invention.